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Cameras/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A boy, Tim, reads from a typed letter. TIM: Dear Tim and Moby, How does a camera work? Signed, Jason. Tim is standing in a photography studio. Photographic lights and other equipment are arranged all around him. TIM: It's funny you should ask, Jason. Because Moby here has become quite the shutterbug lately. A robot, Moby, repeatedly takes Tim's photograph with a hand-held camera, igniting a rapid succession of flashbulbs in Tim's face. TIM: Enough, Moby! The screen goes blank. TIM: You probably already know what a camera does. It takes pictures. Three Polaroid photographs show Tim's face with various uncomfortable expressions. TIM: But there are many different kinds of cameras, instant, automatic, manual, digital, but basically they all have the same job. An image shows an instant, digital, and manual camera. TIM: Cameras focus light onto film, so that it can be made into a picture. MOBY: Beep. TIM: Well, except for digital cameras, which don't use film. But we'll get to that later. All cameras have a lens. An image shows a camera lens. TIM: A lens is made of round pieces of glass or plastic that work together to focus light. An image shows lenses of four different rounded shapes, lined up with light going through them in succession. TIM: It works like the lens in your eye. An image shows an extreme close-up of a brown eye. Moby tosses Tim a small manual camera. Tim catches it. TIM: When you push the button on your camera, it opens the shutter behind your lens. There is a close-up of the camera that Tim is holding. He presses the camera's button. TIM: The shutter is a little sliding door that opens and closes really quickly. An animation shows the interior of Tim's camera. The shutter opens and closes quickly, exposing a piece of photographic film. TIM: In the various film cameras, the open shutter exposes film to light coming through the lens. Film is essentially a thin plastic coated with emulsion, a special gelatin made of crystalized silver halides and other light-sensitive materials. An image shows an exposed roll of photographic film. A close-up illustrates the composition of the film that Tim is describing. TIM: When light hits that emulsion, it causes a chemical change in the silver halide crystals. They break down into dark specs of free silver. An animation shows light hitting some of the film's crystals and darkening them. TIM: The more light you let in, the darker the emulsion gets. MOBY: Beep. TIM: Well, an object has to reflect light to show up on film. That's why pictures taken at night without a flash don't usually come out too well. An animation shows a camera taking a picture of Moby without a flash and it is too dark to see anything. TIM: Let's take a look at Moby for a second. Moby poses in front of a photography screen, with bright lights set up all around him. TIM: All of his parts don't reflect the same amount of light. This bright spot will reflect the most light and cause more emulsion to be darkened. Tim, standing off-screen, taps a pointer on a bright spot on Moby's forehead. A negative of Moby's image appears on one side of the screen, with the bright spot particularly dark. TIM: And that shadow behind him will reflect very little light, so the emulsion in that spot won't react as much. Tim taps the pointer on the shadow behind Moby. That place on the negative image is very bright. TIM: What you're left with is a negative image, a picture where everything's reversed. Tim taps on the negative with the pointer. TIM: All the dark parts are light, and all the light parts are dark. The negative expands to fill the screen. TIM: To make a picture from your film, you shine light through the negative image onto paper coated with the same type of emulsion as your film. An image shows a darkroom. Moby's negative is being projected through an enlarger onto a sheet of photographic paper. TIM: The negative piece of film produces a positive image on paper. An animation shows Moby's image appearing on a sheet of photographic paper. The process is occurring in a darkroom. The darkroom's light clicks on, and Moby is holding a black-andwhite print of his image. He turns toward Tim and frowns. MOBY: Beep. TIM: We used black-and-white film, Moby. That's why you look gray. Color film uses three different kinds of emulsion, one for red, one for blue, and one for green. An image illustrates the three layers of color film as Tim describes them. TIM: Those are the three primary colors of light. See the Color movie to find out more. An image shows three overlapping circles of color. One is red, one is blue, and one is green. The area where the three circles overlap is white. MOBY: Beep. TIM: Well, you're right. These days, film-based cameras aren't that popular. They've been replaced by sleeker, digital cameras, which capture and store pictures in the form of digital data. An image shows a small digital camera. TIM: Instead of hitting film, light coming through a digital camera's lens is captured by an image sensor called a charge-coupled device, or CCD. An animation illustrates light entering the camera's lens and being processed within the camera. TIM: CCDs basically convert light into an electrical signal. They're made up of millions of light receptors called pixels. Each pixel records the brightness of the light hitting it as a number. An image shows a large number of very small squares. At first they are all gray, but then some of them change, forming a black-and-white image of Moby. TIM: Some CCDs have pixels that can tell what color light is hitting them, but most digital cameras detect color using red, green, and blue filters, which are basically pieces of colored glass or plastic. Each filter only allows light of its own color through to the image sensor. An image shows a filter with red, green, and blue squares. A bright white light shines on it. TIM: Software inside the camera converts all that information about light intensity and color into a full-color image. The image can be viewed right away on the camera's electronic viewscreen, saved as a file on a removable memory card, or even transferred directly to your computer. No film required. Images illustrate the three options for image storage that Tim names, using the image of Moby that has just been created. TIM: Alright, these photos are for my grandparents, so be nice. Tim and Moby are standing inside a photo booth. The booth's curtain is drawn, and only their feet are visible from outside the booth. MOBY: Beep. TIM: Hey! There is a flash inside the booth. TIM: Ow! There is another flash. TIM: Ah! The strip of photos from the booth shows Moby making "rabbit ears" over Tim's head, playing with Tim's face, and otherwise ruining each picture. TIM: Never easy with you, is it? MOBY: Beep. Category:BrainPOP Transcripts Category:BrainPOP Engineering & Technology Transcripts Category:BrainPOP Arts & Music Transcripts